Power management techniques for computer systems and processors typically use sleep states. For example, to save energy when the processors are idle, the processors can be commanded into a low power state or sleep state. These states typically cut the clock signal and power from idle units inside the processors. The more units that are stopped by cutting the clock, reducing the voltage, or completely shutting down, then the more energy that can be saved. However, the more circuits and signals that are turned off, then the more time the processors will need to wake-up. The power states are called the C-states (e.g., C0-C6) with C0 being the operating state with the processors fully turned on and C6 being the deep sleep state that reduces the internal voltage of one or more processors to any value including 0 volts. C6 suffers from long latencies (several tens of microseconds) and C6 can not be efficiently used for dead times less than a few hundred microseconds.
Furthermore, software inefficiencies, and its requirements of hardware, have also caused an increase in computing device energy consumption. In fact, some studies indicate that computing devices consume a sizeable percentage of the entire electricity supply for a country, such as the United States of America. As a result, there is a vital need for energy efficiency and conservation associated with integrated circuits. These needs will increase as servers, desktop computers, notebooks, ultrabooks, tablets, mobile phones, processors, embedded systems, etc. become even more prevalent (from inclusion in the typical computer, automobiles, and televisions to biotechnology).